Re-closable plastic containers are known for pharmaceutical, cosmetic or other products, which are made by blowing and/or moulding, in two parts, one of which is composed of the container body, while the other part is composed of closing means, to keep the container closed after its manufacture and to close it again after use.
In these containers, the closing means remain fitted in the neck of the container, or coupled with this, until this is opened for the first time to be used.
Consequently, the part of the closing means in contact with the container neck is protected against external polluting agents, which cannot deposit on this and, therefore, the risk of said polluting agents being accidentally introduced inside the container when this is closed again after a first use with the same closing means is extremely limited.
The above containers are nevertheless costly to make as they require separate moulds for the two parts of the container, which also have to be assembled after moulding.
Re-closable plastic containers are also known, for pharmaceutical, cosmetic or other products, which are made by blowing and/or moulding in a single piece, in which i.e., the container body is made in a single piece with the closing means suitable for keeping the container closed after its manufacture and/or for closing this after use.
A container of this type is the subject of the Italian utility model patent Nr. 199.776, which describes a single-dose or multi-dose container for pharmaceutical products comprising a body having a lower opening sealable by sealing and an upper neck, closed on top by closing means in the form of a peduncle, obtained all one piece with it and with a cap having shutter means to close the container neck again after this has been opened by tearing the peduncle, the shutter means being obtained on the part of the cap turned in the opposite direction with respect to the container neck.
These containers are undoubtedly cheaper to make than the previous ones, but have the drawback that the closing means have to be obtained on the outside of the container during moulding.
The part of the closing means that has to be used to close the container again after use, in point of fact remains exposed to external polluting agents which can thus easily enter the inside of the container when this is closed again after a first use.
This circumstance is considerably hazardous, especially in the case of the containers being used to contain pharmaceutical substances.
A further type of re-closable containers made in a single piece is the subject of the industrial invention patent nr. 1.287.450 and consists of a hollow body, having a dispensing mouth, and of a closing cap that has a shutter pin obtained on the part turned towards the mouth.
During moulding, in point of fact, the hollow body and the cap are made slightly distanced the one from the other, with the shutter pin aligned and facing the dispensing mouth, but not in contact with this.
Furthermore, the hollow body and the cap are connected together by means of a pair of thin straps which, after moulding, allow these to be moved closer or away from each other to allow the coupling/uncoupling of the shutter means with/from the dispensing mouth.
This latter type of containers also has several drawbacks however, including the fact that they require particularly complex moulds, that are difficult to make, and do not permit obtaining high-quality containers.
In this respect, it should be considered that the traditional moulds usually consist of a pair of half-shells inside which a core can be fitted for forming the inner surface of the hollow body.
At the shutter pin, the bringing together of the two half-shells determines the formation of a thin line of burr.
Such line of burr extends along the entire length of the pin and is such as to prevent the sealed coupling of the shutter pin with the mouth of the container in closing configuration.
There is therefore a very high risk of negatively affecting the sterility of the product inside the container.